The present invention generally relates to heart valve repair and replacement techniques and annuloplasty devices. More specifically, the invention relates to the repair and/or replacement of heart valves having various malformations and dysfunctions.
Diseased mitral and tricuspid valves frequently need replacement or repair. The mitral and tricuspid valve leaflets or supporting chordae may degenerate and weaken or the annulus may dilate leading to valve leak (insufficiency). The leaflets and chords may become calcified and thickened rendering them stenotic (obstructing forward flow). Finally, the valve relies on insertion of the chordae inside the ventricle. If the ventricle changes in shape, the valve support may become non-functional and the valve may leak.
Mitral and tricuspid valve replacement and repair are traditionally performed with a suture technique. During valve replacement, sutures are spaced around the annulus (the point where the valve leaflet attaches to the heart) and then the sutures are attached to a prosthetic valve. The valve is lowered into position and when the sutures are tied, the valve is fastened to the annulus. The surgeon may remove all or part of the valve leaflets before inserting the prosthetic valve. In valve repair, a diseased valve is left in situ and surgical procedures are performed to restore its function. Frequently an annuloplasty ring is used to reduce the size of the annulus. The ring serves to reduce the diameter of the annulus and allow the leaflets to oppose each other normally. Sutures are used to attach a prosthetic ring to the annulus and to assist in plicating the annulus.
In general, annuloplasty rings and replacement valves must be sutured to the valve annulus and this is time consuming and tedious. If the ring is severely malpositioned, then the stitches must be removed and the ring repositioned relative to the valve annulus during restitching. In other cases, a less than optimum annuloplasty may be tolerated by the surgeon rather than lengthening the time of surgery to restitch the ring.
During heart surgery, a premium is placed on reducing the amount of time used to replace and repair valves as the heart is frequently arrested and without perfusion. It would be very useful to have a method to efficiently attach a prosthesis into the mitral or tricuspid valve position. Furthermore such a method may have its greatest advantage in remotely attaching a valve repair or replacement device so that surgery could be avoided altogether.
Annuloplasty devices and methods and heart valve repair and replacement devices and techniques are therefore necessary to provide a more reliable and more easily accomplished valve repair and replacement.
The present invention generally provides a device for repairing a heart valve having an annulus and a plurality of leaflets for allowing and preventing blood flow through a patient""s heart. The device comprises a first support ring and a second support ring connected to the first support ring to form a coiled configuration. The first support ring is configured to abut one side of the valve annulus and the second support ring is configured to abut an opposite side of the valve annulus to thereby trap valve tissue, that is, annulus tissue and/or leaflet tissue, therebetween. This device may be used in those situations, for example, that have conventionally utilized annuloplasty rings, but the device of this invention may be applied in a much easier manner. The device may also be used to carry a replacement heart valve. The invention contemplates various embodiments of the device, including embodiments for catheter-based surgery and embodiments for open heart surgery.
In the various embodiments, the first and second support rings may have an inner core covered by an outer layer, such as a fabric layer, with the inner core being formed from a more rigid material than the outer layer. The first and second support rings may have generally triangular-shaped cross sections with flat sides opposing one another and trapping valve tissue therebetween. A plurality of fasteners may be used between the first and second support rings and, for example, these may comprise sharp projections. An actuating member may be used to actuate the fasteners to an extended position through the valve tissue. Other forms of fasteners are possible as well, including those comprising projections and complimentary receiving members on the first and second support rings. Shape memory alloys may be used to facilitate connection, such as by moving the first and second support rings together or moving fastening elements thereof into engagement.
At least the opposed surfaces of the first and second support rings may be roughened, such as by the use of fabric, coatings, knurling or the like to facilitate better engagement and retention of the support rings on the valve tissue. A removable sleeve may be carried by the first and second support rings for initially reducing friction between the respective rings and the valve tissue during initial engagement therewith, such as during rotation of the device on either side of the annulus. The sleeve may then be removed to expose the higher friction surfaces of the device to the valve tissue for better retention.
Preferably, the first and second support rings are formed integrally from a coiled rod, such as a metallic rod, with one end of the rod formed as a leading end and one end formed as a trailing end. These ends may be bent in opposite directions so that the leading end may be directed through the valve tissue and the trailing end may be grasped by an appropriate surgical implement. A carrier may be used to rotate the device into position on opposite sides of the valve annulus and then may be removed leaving the first and second support rings in place to trap the valve tissue therebetween. As another alternative, the carrier may be coil-shaped and the repair device may be rotated into place on only one side of the valve annulus similar to conventional rings. The carrier may then be rotated for removal while leaving the repair device in place. The first and second support rings may be adjustable in diameter to allow adjustment of the valve annulus.
When replacing a heart valve, a device of this invention again preferably comprises first and second support rings formed in a coiled configuration with a replacement valve coupled to at least one of the support rings. The replacement valve may be coupled in a releasable manner using any suitable fastening structure. For example, the replacement valve and one of the support rings may include mating engagement elements or the replacement valve may be directly threaded into one of the support rings. The replacement valve and one of the support rings may alternatively include respective cuffs adapted to receive sutures to fasten the replacement valve to the support ring. Optionally, one of the support rings may include a cuff with a movable fastening element which is engageable with the replacement valve. The fastening element may be formed from a shape memory alloy to facilitate its movement between an engaged and a disengaged position relative to the replacement valve.
The invention further contemplates various methods of repairing a heart valve including methods for fully replacing the heart valve. Generally, the method includes inserting a first end of a coil-shaped support through the tissue of a heart valve. A first ring of the coil-shaped support is then rotated in position on a first side of the annulus and a second ring of the coil-shaped support is positioned on an opposite side of the annulus. The first and second rings may then be fastened together to trap the annulus tissue therebetween, or the inherent resilience between the first and second rings may trap tissue without using separate fasteners. The coil-shaped support may be carried in its coiled form during the rotation step, or the coil-shaped support may be extended from a catheter positioned adjacent the annulus. Many other variations of these methods and additional methods will be apparent to those of ordinary skill upon review of this disclosure.
Various additional objectives, advantages and features of the invention will become more readily apparent to those of ordinary skill in the art upon review of the detailed description of the illustrative embodiments.